I'm trying to make some drill down to our system ELK before upgrading.
We are running ElasticSearch with 1.7 (old, I know).
I've found that on ES data directory, we have some indices that not exists by ES (not shown on /status request or /_cat/indices)
It is some Logstash data from 2017 and we don't need it any more.
I just want to make sure it is fine to delete those files without any request for ES (just rm - rf logstash-2017*).
What do you think?